112 



The general distinction between the western and eastern half of 

 this continent, and the resemblance of the insect fauna of the 

 former to that of Europe, is shown bj the citation of a large 

 number of important genera which do not occur in eastern 

 America, but are found in both the other regions. 



In an analytical comparison of the butterfly faunas of eastern 

 North America and of Europe, I have shown the greater rich- 

 ness of the European fauna, and have pointed out some curious 

 disparities in the proportions of the numbers of members be- 

 longing to different groups. Europe proves to be peculiar for 

 its wealth in brush-footed butterflies, America in skippers ; and 

 this difference is largely due to the fact that there are more 

 than four times as many Satyrids in Europe as in America, and 

 five times as many small skippers in America as in Europe. 

 Other minor groups, which are much better represented in 

 Europe than in eastern America, are the blues (38 to 13), 

 orange-tips (7 to 2) and Parnassii (6 to 0) ; while the 

 groups disproportionately abundant in eastern America are the 

 hair-streaks (20 to 10), the yellows (20 to 10) and the 

 swallow-tails (9 to 8). A minuter analysis shows similar or even 

 greater disparities, so that we find only one-fourth of the North 

 American genera represented in Europe. The derivation of 

 our present fauna is believed to be largely from the south. 



Mr. V. T. Chambers has published some remarks on the 

 distribution and geographical peculiarities of the Tineina of 

 Colorado. He shows that the range of the species is generally 

 dependent upon that of the food-plant, and that they scarcely 

 occur above timber line. He also finds them rather plainer or 

 more obscurely colored in Colorado than in the Mississippi 

 Valley, Colorado having in fact an unusually large ])roportion 

 of uncolored sp cies. 



Dr. A. S. Packard, Jr. has made us acquainted with a new 

 cave-fauna at the southern extremity of Great Salt Lake, 

 nearly as characteristic as that found in the caverns of Ken- 

 tucky, Indiana and Virginia. In a straight gallery less than 

 one hundred metres long, in which the darkness was not total, 

 he found a bleached Poduran, of a species which is widely dis- 

 tributed in this country and in Europe, but which occurs in this 



